Flour sifter vibrated by electric motor having an unbalanced shaft



Dec. 29, 1953 D DUNN 2,664,201

FLOUR SIFTER VI BRATED BY ELECTRIC MOTOR HAVING AN UNBALANCED SHAFT Filed NOV. '7, 1949 2 Sheets-Shae 1 3nventor DflP/D L, D N/Y D 29, 1953 D. L. DUNN 2,664,201

FLOUR SIFTER VIBRATED BY ELECTRIC MOTOR HAVING AN UNBALANCED SHAFT Filed Nov. 7, 1949 2 Sheets-Sheet 2 r Liza-La 47f I, I 7 TM Enventor (Ittorneg Patented Dec. 29, 1953 UNITED STATES PATENT OFFICE FLOUR SIFTER VIBRATED BY ELECTRIC MOTOR HAVING AN UNBALANCED SHAFT removably applied to opposite sides thereof, and

providing for ready and repeated sifting of a ma terial from one bowl to the other merely by inverting the device after each passage of material through the sifting unit.

It is the principal ob ect of this invention to provide a sifter of the above stated kind having a novel, practical and reversible sifting unit functionally operable by means of a self-contained, electric motor with unbrlanced shaft, and free of any movable connections that are subject to wear or looseness incident to use.

It is a further object of the present invention to provide a device of the above character, comprising a sifting unit wherein the elements through which the material is sifted, and the selfcontained electric motor are supported by resilient means and the rote ting element of the motor is eccentrically weighted in a manner whereby a vibratory action of the sifting element is automatically set up incident to the operation of the motor.

It is also an object of the invention to provide a sifter in which there is no relative movement between the motor and the sifting elements and wherein the vibrztory action of the latter is in accordance with the speed of rotation of the motor and resiliency of the support.

Yet another object of my invention is to provide means for easily and readily attaching the bowls to the sifting unit and permitting easy release of one or both therefrom.

Still further obiects of the invention reside in the details of construction of the various parts and in their relationship and mode of use as will hereinafter be fully described.

In accomplishing these and other objects of the invention, I have provided the improved details of construction, the preferred forms of which are illustrated in the accompanying drawings, wherein- Fig. 1 is a side view of a sifter embodying the improvements of the present invention therein.

Fig. 2 is a top view of the sifter, with most of the upper bowl broken away to better show the character of and location of the sifting unit within the enclosing frame.

Fig. 3 is a fragmental sectional detail of the sifting unit frame and bowl securing. latches.

Fig. 4 is a fragmentary view, particularly illustrating the construction of the sifting unit and manner of attaching the bowls to the opposite sides of the sifter frame.

Fig. 5 is a cross-sectional view of a sifting unit of an alternative form of construction.

Fig. 6 is a cross-sectional view of another alternative form of sifting unit.

Referring more in detail to the drawings:

In Fig. 1 I have illustrated the sifter in its present preferred form of construction. It is shown to comprise a centrally located, reversible siftingunit, designated in its entirety by reference number l0 and the receptacles, or bowls II and I2, applied to opposite sides thereof. The sifting unit comprises an annular frame l3 which contains the sifting elements, and mounts the bowls thereon. It is equipped with an integral and radially extending handle H. The frame and handle might be one piece construction, but preferably it is diametrically divided along the axial line of the handle, thus providing opposite halves which, upon being properly assembled, are secured together by screws l5 passed through the handle and through the ends of the semi-circular parts opposite the handle. This form of construction facilitates assembly of parts and simplified manufacture.

Contained within the annular frame l3 are the sifting elements l6 which for convenience will be referred to as screens. In the sifting unit of Fig. 1, two screens are employed. While in the alternative forms of construction shown in Figs. 5 and 6, one screen is used in each.

Each screen in the device of Fig. 1 comprises a light weight metal disk formed with a multiplicity of small, closely related perforations Hip, as has been shown in Fig. 2. The central portion of each disk is imperforate, for a purpose presently explained.

As a means of vibrating or agitating the screens 16, I employ a small electric motor 20 which is fixedly mounted within a sealed, enclosing housing 2|. This housing is disposed centrally within the frame 13 as observed in Figs. 2 and 4 and it is fitted with a resilient, annular mounting ring 22, made of rubber of other suitable material. This ring 22, in turn, is supported concentric-ally within the annular frame 13 in the medial plane thereof. The means of support for the ring 22 comprises a plurality of rigid and radially directed spokes 24, one of the spokes, designated in Figs. 2 and 4 by numeral 242:, is of tubular form and is extended axially of the handle for passage of circuit wires 25 therethrough, to the electric motor 20.

At their outer ends the spokes 24, are fixed in the frame I3 and at their inner ends are suitably secured to the ring 22.

The ring 22 which is the shock mounting for the motor and sifting elements, is of channel form in cross-section and is made of a material that will properly support the unit and at the same time permit the desired vibratory action thereof. The electric motor 20 is supported with its axis perpendicular to the plane of the frame I3 and coaxial of the frame opening. The motor shaft 2% is equipped at its ends with eccentrically mounted Weights 26 whereby the shaft is unbalanced and upon rotation causes 2. vibratory action to be set up in accordance with the speed of the rotation of the shaft.

The two screens l6 employed in the device of Fig. 1 are of the same diameter and coaxially disposed. They are applied, respectively, to top and bottom sides of the housing 21; each being formed central!" with .a semi-spherical domelike portion [8d fitted over the adjacent portion of the housing. The disks are secured to the housing by screws 28 passed theret-hrough at the center and threaded into the housing wall. Immediately about the dome-like portions AM, the disks are seated against the opposite faces of the ring -22 and are .thus held in spaced, parallel .planes by the ring. Also, they are located within the planes of the opposite faces of the frame it, as will be understood by reference to Fig. 4. The outside diameter of the screens IE is such that very slight clearance is provided between their peripheral edges and the inner wall surfaces of the frame 13; this clearance being suflicient only to permit the intended vibrator-y action of the screens.

The bowls .H and 12, which are applied to opposite sides of the frame .I-3,-are-of such-diameter that they may be seated at their open ends against the opposite faces of the annular frame I 3, in registration with the opening .therethrough, for the passage of the material to be sifted from one to the other through the sifting elements. As seen best in Fig. .4. .the frame 13 is formed at opposite sides, and about the opening therein, with annular, counter-sunk seats 30, within which the edges of the bowlsare engaged. Also, each bowl is formed near its edge, with an encircling and projected flange 35 adapted to seat against the face of the frame.

To secure the bowls in place, when applied to top and bottom sides of frame 13 as shown in Fig. 1, the frame has been formed, at the handle side and at opposite faces, with projecting flanges, as at 36 and 361s, and these are formed with inwardly facing channels 3'i'3'l designed to receive the adjacent portions of the flanges 35 of the bowls therein when the bowls are properly applied to the frame. At that side of the frame 13 which is directly opposite the handle, a spring clip 48 is applied thereto. Thi is secured in the frame with its opposite end portions extended to opposite sides of the frame, and formed with hooks 42 designed to holdingly engage over the adjacent portions of the flanges 35 of the bowls, thus to secure them to the frame. These hooks have angularly extending release portions whereby the hooks may be depressed and disengaged from the bowl flanges, thus to permit removal of the bowls from the frame.

The bowls H and 12 may be of various sizes and made of glass, plastic or metal. However,

one sifting element.

it is preferred that they be made of a transparent glass or plastic so as to permit the user to see the ingredients contained therein. It is preferred also that the bowls be substantially identical and interchangeable, so that either bowl may be secured to either side of the frame 13. As is illustrated in Fig. 1, the bowls may be graduated to indicate the quantity of material contained therein.

In Fig. 5, an alternative form of sifting unit has been illustrated. This unit employs but In this construction an annular, rubber shock mounting 45 of channelform in cross section, is fitted and secured within the frame [3- and the screen, I811, which is of disk form, has its peripheral edge sealed in a groove 4'! in the shock mounting. The motor housing is somewhat simplified in that it does not employ an enclosing housing, corresponding to housing 2! of the device of Fig. 4, but the motor 20 is supported directly by thescreen disk and semi-spherical domes 4843 are applied to the screen-at opposite sides to enclose the motor.

In Fig. 6 another alternative form of construction has been illustrated. This employs a single vibrator screen [51) and the electric motor is applied centrally within the screen as in Fig. 5, and is enclosed within domes 5C-50 applied to opposite sides of the screen. Shock mountings 5555, of rubber or other suitable material are applied to the housing directly above and below the axis of the motor. '1' hese resilient mount ings are supported by arched bars 5558 applied to the frame l3 diametrically across the opening therein and at opposite sides of the screen, and secured at their outer ends in the frame.

It will be noted that in this latter form of construction, the periphery of the vibrator screen, which is of disk-form is close to the wall of the enclosing frame, with only the clearance necessary for its sifting action.

The various sifting devices, as hereinbefore described, perform their sifting functions in the following manner: First, the flour or other material to be sifted, is placed in one of the bowls. Then the frame I3 and two bowls are assembled and secured together by means of the clip 40, as shown in Fig. 1. Then the frame is inverted so that at the start of the sifting operation the material to be sifted is contained in the inverted upper bowl. The electric motor 20 is then energized and the screen or screens are caused to be agitated, to cause the material to be sifted through into the lower bowl. If another or multiple sifting is desired, it is only necessary to invert the unit after each sifting operation; this being repeated until the material has been sifted to the extent desired. Then the bowl containing the material may be detached and the material used.

If desired, one bowl might be removed from the sifter "and the final sifting could be directly into a mixing bowl or the like.

While the various modifications are slightly different in details of construction, they are alike in principle and in mode of use.

Having thus described my invention, what I claim as new therein and desire to secure by Letters Patent, is:

l. In a sifter of the character described, a sifter unit comprising an annular frame member defining an opening for the passage of siftable material from one side of the said frame member to the other, an electric motor disposed within said opening; said motor having an unbalanced shaft disposed substantially coaxially of said opening and with its axis parallel to the axis of the annular frame member, a housing enclosing and supporting the electric motor and spaced from the annular frame member, a resilient shock ring encircling and fixed to the said housing in the plane of the annular frame member, a support for the motor housing attached to the annular frame member and to the shock ring, and. a sifting screen supported the motor housing for vibratory action under the influence of vibratory action of the motor and bridging the space between the motor housing and the annular frame member, and the said motor housing being positioned in the plane of the sifting screen.

2. A sifter as in claim 1 wherein the support for the motor housing comprises a plurality of rigid spokes directed radially therefrom and wherein the said sifting screen comprises upper and lower screen elements mounted in parallel relationship on the motor housing and at opposite sides of the said spokes.

DAVID L. DUNN.

References Cited in the file of this patent UNITED STATES PATENTS Number Name Date 690,731 Jamieson Jan. 7, 1902 1,328,576 Lindsay Jan. 20, 1920 1,357,292 Lowe Nov. 2, 1920 1,518,236 Walcott et a1. Dec. 9, 1924 1,750,976 Sturrock Mar. 18, 1930 2,274,914 Wilcox Mar. 3, 1942 2,284,671 Meinzer June 2, 1942 2,393,453 Bailey Jan. 22, 1946 2,412,840 Snyder Dec. 17, 1946 

